Territory Stories

Woodgreen, Northern Territory : explanatory notes



Woodgreen, Northern Territory : explanatory notes

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Northern Territory Geological Survey


E-Publications; E-Books; PublicationNT; Australia 1:100 000 Geological Map Series




Australia 1:100 000 Geological Map Wood 5458; Australia 1:250 000 Geological MapAlcoota SF5310; Australia 1:250 000 Geological MapAlcoota SF5310

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1:100 000


Made available via the Publications (Legal Deposit) Act 2004 (NT); Available from GEMIS - Geoscience Exploration and Mining Information System




Geology; Georgina Basin; Arunta Region

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Northern Territory Government; Northern Territory Government

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1st ed.


Australia 1:100 000 Geological Map Series

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Attribution International 4.0 (CC BY 4.0)

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Northern Territory Government



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https://geoscience.nt.gov.au/gemis/ntgsjspui/handle/1/81885 [GEMIS]

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25 (eg 550 ppm and 80 ppm), but contains no significant Sn mineralisation (Frater 2005). Uranium In 1971, Pechiney, in joint venture with Kratos Uranium, flew a radiometric survey over delny and dneiPer, east of Woodgreen. Anomalies were located over basement igneous and metamorphic rocks similar to those in Woodgreen. No uranium mineralisation was detected (Lehmann and Mannoni 1971). Radiometric anomalies, possibly due to uranium, have been detected in gammaray logs of Cenozoic sediments in water bores in Woodgreen (Shaw and Warren 1975). Prompted by the Yeelirrie discovery in Western Australia, CRA Exploration conducted regional exploration for Tertiary calcretehosted uranium. Work subsequently focused on the TiTree Basin but was unsuccessful (Hughes 1972). Otter Exploration flew a spectrometer survey in 1977 as part of a search for uranium or scheelite mineralisation. Followup groundwork failed to detect any significant mineralisation and the licence was relinquished in 1979 (Kojan 1979). In the early 1980s, CRA Exploration undertook multicommodity airborne geophysical and drainage geochemical exploration, including selected areas targeted for unconformityrelated uranium, but this was unsuccessful (Menzies and Louwrens 1995). Gold A joint venture between Track Minerals and Eon Metals was granted tenure in 1988, with the intentions of exploring for gold in ironstone outcropping near Mollie Bluff, and following up a radiometric anomaly that was defined by Otter Exploration as a gold target. This target is in the Tops Member of the Central Mount Stuart Formation near 446800mE 7551000mN,16 km northeast of the cupriferous horizon at Mount Skinner. It has rock chip assays of lateritic shale up to 110 ppm Pb, 100 ppm Cu and 290 ppm Zn (Dashlooty 1989). All surface rock chips and unspecified samples from previous drilling at Mount Skinner were analysed for Au. Results were less than ppm Au and the licence was relinquished without further work. Diamonds In the early 1980s, a joint venture between Alcoa and Western Mining explored for diamonds in Woodgreen without success (Chuck 1983). CRA Exploration explored parts of BARROW CREEK and ALCOOTA for diamondiferous kimberlites during the 1990s. Several circular geomorphological features in Woodgreen were inspected, but not considered worthy of follow up. No diamonds or diamond indicator minerals were recorded during reconnaissance gravel sampling. Reevaluation of the aeromagnetic data failed to identify any significant dipolar anomalies indicative of diatremes (Louwrens 1996). Groundwater Detailed information regarding groundwater in Woodgreen, and the location and other details of specific waterbores is obtainable from the Water Resources Branch, Natural Systems Division of the Department of Natural Resources, Environment and the Arts, Alice Springs. Aquifers in Woodgreen can be subdivided into three broad stratigraphic categories: Palaeoproterozoic metamorphic and igneous basement rocks of the Arunta Region; lithified Neoproterozoic to Cambrian sedimentary rocks of the Georgina Basin; and lithified to unconsolidated sediments of the Cenozoic TiTree Basin and associated palaeochannels. Aquifers in the generally nonporous basement rocks are likely to be irregular, small and difficult to predict, and the success rate has been low (Shaw and Warren 1975, McDonald 1990). The most important Georgina Basin aquifers are in CambroOrdovician and Devonian sedimentary rocks (Shaw and Warren 1975, Haines etal 1991), which are not exposed in Woodgreen. Successful bores have been sunk into Neoproterozoic strata, but yields are usually low and high salinity is common (Shaw and Warren 1975, McDonald 1990). This is likely to be at least partly the result of interbedded evaporites, which have been intersected in mineral exploration drillholes. Shaw and Warren (1975) reported that the CambroOrdovician Tomahawk Formation contains good aquifers and that 90% of bores drilled into the unit have been successful. Although this formation does not outcrop in Woodgreen, it is likely to be present at shallow depths beneath Cenozoic cover in the extreme northeastern corner of the sheet area. The hydrogeology and groundwater resources of the TiTree Basin have been studied in detail by McDonald (1990). Only the eastern margin of the basin, and associated palaeochannels, are present within Woodgreen, but this basin provides the most reliable water resources in the area. AcKnowlEdgEMEntS The authors gratefully acknowledge the friendly cooperation of pastoralists on Mount Skinner and Woodgreen stations during fieldwork. John Dunster (NTGS, Darwin) contributed to the Economic geology section. David Greene (Denison University, Ohio, USA) is thanked for discussions on the structural geology of the region. Figures were prepared by Kathy Johnston, who also formatted the document. rEFErEncES Buick IS, Miller JA, Williams IS and Cartwright I, 2001. Ordovician highgrade metamorphism of a newly recognised late Neoproterozoic terrane in the northern Harts Range, central Australia. JournalofMetamorphic Geology 19, 373394. Chuck RG, 1982. Annual report for EL 2654 Mount Skinner, NT for the period 24/1/81 23/1/82. Alcoa of Australia Ltd. Northern Territory Geological Survey, Open File CompanyReport CR19820183. Chuck RG, 1983. Base metal exploration in EL 2654, Mount Skinner, central Australia, final report. Alcoa of Australia Ltd. Northern Territory Geological Survey, Open File CompanyReport CR19830125. ClaouLong JC and Hoatson DM, 2005. Proterozoic maficultramafic intrusions in the Arunta Region,